Apparatus, systems and methods for sensing bladder fullness

ABSTRACT

Embodiments of the invention provide devices and systems to monitor fullness of a patient’s bladder. One embodiment of a bladder fullness (BF) measure system comprises a sensor device (SD) and a controller. The SD generates an output signal (OS) based on the force exerted by the bladder against SD the wherein the OS corresponds to a degree of BF. The SD may be attached to the bladder wall or adjoining tissue and positioned between the bladder and the pubic bone such that the SD is not affected by tissues force other than that from the bladder. The controller connects to the SD and causes an associated implant to perform a function when the SD output signal exceeds a predetermined threshold. Embodiments are particularly useful for providing information on BF to patients suffering from spinal injury or other conditions whereby they have lost the ability to sense BF and/or voluntarily urinate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. application Serial No. 16/536,197filed Aug. 8, 2019, now allowed, which, in turn, claims the benefit ofU.S. provisional application Serial No. 62/715,983 filed Aug. 8, 2018,the disclosures of which are hereby incorporated in their entirety byreference herein.

BACKGROUND

1. Field of the Invention. Embodiments of the invention relate tomedical apparatuses and methods. More particularly, embodiments of theinvention relate to systems, devices, apparatus, and sensors formeasuring real-time information regarding bladder fullness. Still, moreparticularly, embodiments of the invention relate to systems and methodsfor providing real-time information on bladder fullness to patients whohave lost bladder control to allow them to selectively control urinaryfunction utilizing such information.

Many disorders can result in loss of a patient’s ability to voluntarilycontrol bladder function. Most commonly, patients suffering from spinalcord injuries can lose not only the ability to voluntarily controlurination, but also the ability to sense when the bladder is full. Suchpatients have usually had to rely on the chronic use of a Foley catheterwhich is placed through the urethra and has a distal tip residing in thebladder. However, the use of Foley catheters for these patients has anumber of drawbacks. In particular, the use of Foley catheters for thesepatients presents a constant risk of infection of the patient’s urinarytract which is exacerbated by the frequent need to exchange for a newcatheter. Moreover, Foley catheters usually drain into a bag which thepatient must carry when away from home or a treatment facility. The needto carry the drain bag is a significant burden to many patients.

To at least partially overcome these problems, very promising newsystems have been proposed which allow patients and their caregivers toselectively stimulate the pudendal or other nerves to control voiding ofthe bladder. Such systems can eliminate the need for Foley catheters andare described, for example, in U.S. Pat. Publication 2014/0249595, thefull disclosure of which is incorporated herein by reference.

While a significant advance, such nerve stimulation systems do not alertthe patient when their bladder is full. Since many patients will havelost the ability to sense when the bladder is full, these patients mayprolong periods between voiding, raising the pressure in the bladderabove safe levels and risking injury and infection of the kidneys.

For these reasons, it would be desirable to provide systems and deviceswhich provide feedback to a patient or caregiver regarding fullness ofthe patient’s bladder.

SUMMARY

Various embodiments of the invention provide apparatus, systems andmethods for providing information including real time information on thedegree of fullness of a patient’s bladder. In particular embodiments,the apparatus/system is able to measure a degree of fullness of thepatient’s bladder. The apparatus includes a sensor, typically a pressuresensor which is able to sense an amount of force applied to theapparatus by the bladder. According to one or more embodiments, theapparatus and/or system may be configured to generate information for acontrol system such as a closed loop system that is used to initiate andcontrol voiding of the bladder. Such a control system can be configuredto receive a signal (electrical/analog or digital) from the sensorrepresentative of bladder volume and use that signal to void the bladderwhen the pressure sensor signal goes beyond a threshold value. Thetrigger threshold may be based on the percent change in the signalgenerated by the pressure sensor between pre-determined bladder volumesrepresenting “empty” and “full.” This percent change will henceforth bereferred to as delta or Δ. A large Δ provides for better efficacy of thebladder fullness measurement (BFM) apparatus in terms of its use with anassociated bladder control system.

One advantage of the BFM apparatus over other sensor technologies todetermine bladder fullness is that the BFM apparatus does not need to bepositioned within the bladder by catheterization that is, it does notneed to be attached to a Foley catheter or other urinary drainage devicethat is permanently left in place in the patient’s urinary tract (thisis advantageous since it reduces the risk of infection associated withFoley catheters or other like urinary drainage device). Instead, invarious embodiments, the BFM apparatus can be attached directly to thebladder wall (e.g., using a suture or other attachment means known inthe medical arts). Also, according to some embodiments, it may beimplanted with an associated electrical stimulation system (e.g., apulse generator) configured to provide for electrically evoked urinationbased on a signal(s) received from the BFM apparatus and then functionwithout any further action required by the patient.

In various configurations, embodiments of the BFM apparatus can beconfigured to be attached to the bladder and positioned between thebladder wall and the pubic bone so that the pressure sensor is onlyeffected by force exerted by the bladder wall (e.g., due to degree offullness) and remains substantially unaffected by force exerted by othertissue (e.g., from the intestines). In particular embodiments, the BFMapparatus can be sutured to the connective tissue adjacent the bladderwall. In use, such embodiments provide the advantage of reducing signalnoise or motion artifact resulting from movement of other organs ortissue (e.g., the intestines, lungs, heart, etc.) besides the bladder.This in turn improves both the accuracy and precision of measurements ofbladder fullness. Another advantage of the BFM apparatus is that itspower source does not require high voltage or magnetic fields. Thus, itcan be powered by a low voltage long lasting battery which may beconfigured to be rechargeable by induction coupling with a chargingdevice placed on or near the surface of the abdomen.

Various embodiments of the bladder sensor may be used to provideinformation for monitoring bladder fullness for a variety of uses. Forexample, according to one embodiment, information provided by the sensormay be used by a physician to assess the patient’s bladder function anddiagnose related conditions such as neuropathy or damage of the nervescontrolling bladder function (e.g., the pudendal nerve), overactivebladder, incontinence and related conditions. In additional embodiments,the bladder sensor may form part of a closed-loop neuro-stimulationsystem which can be used to provide neuro-stimulation therapy to treatone more urinary related conditions. Such neuro-stimulation therapy canbe used for a number of functions including for example, urinationinitiation and control, to prevent or reduce overactive bladder or toincrease pelvic floor muscle tone or urinary sphincter pressure, orboth, and thereby prevent involuntary urine leakage.

Embodiments of the invention are particularly useful for monitoring andproviding information on the degree of fullness of a patient’s bladderparticularly for those patients who have lost the ability to sensebladder fullness and/or voluntarily urinate due to spinal cord injury orother condition affecting the functionality of one or more of theirspinal cord, pudendal nerves, or other neural pathway involved in theurination process.

The invention also contemplates a neuro-stimulation system and methodthat make use of such a BFM apparatus for alleviation of urinaryincontinence. The BFM apparatus may be able to detect the fill stage orcontraction of the bladder at any given time, and provide signalsindicating such conditions to components of the neuro-stimulation systemsuch as an implanted neuro-stimulator, an external programmer or a datarecorder.

In one aspect, the invention provides a bladder sensor apparatus forsensing or monitoring fullness of the patient’s bladder comprising abase which comprises a flexible material, a rigid layer attached to thebase, a deformable membrane positioned over and hermetically sealed tothe rigid layer, and a pressure sensor. The base is configured to bepositioned in and attached to tissue between the pubic bone and thebladder and to conform to a contour of the pubic bone so as to bemechanically supported by the public bone. In particular embodiments,the bases is positioned near the pubic bone such that mechanical supportprovided by the pubic bone to the base prevents the membrane from beingsubstantially deformed by force from tissue other than the bladder.

The rigid layer may comprise various metals (e.g., stainless steel) orrigid polymers known in the art, though desirably at least a portion ofthe rigid layer comprises a conductive material such as a metal orconductive polymer. The deformable membrane, which is sealed to therigid layer defines a cavity between the membrane and the rigid layer.The cavity is filled with a fluid such a mineral oil or silicone. Themembrane is positioned and configured to deform from force exerted bythe bladder against the membrane so as to exert a pressure on the fluid,with the pressure correlated to a degree of fullness of the bladder. Thedeformability of the membrane may be achieved by the selection of itsdimensions and the use of various deformable materials known in the artsuch as metals and polymers including, various elastomers known in theart.

The pressure sensor is positioned on a portion of the rigid layer withinthe cavity such that it is able to measure the pressure of the fluidwithin the cavity. The sensor generates a signal (electrical or digital)correlated to the pressure within the cavity which is in turn iscorrelated to a degree of fullness of the bladder. It is electricallycoupled to the conductive portion of the rigid layer such that signalsgenerated by the pressure sensor can be transmitted to via theconductive portion to a controller or other electrical circuitry. It maybe attached to the rigid layer via various adhesives known in the artand may be electrically coupled to the conductive portion by solder orother electrically conductive means. According to various embodiments,the pressure sensor may correspond to one or more of a strain gauge, asolid state sensor or a MEMS-based sensor. Also, according to someembodiments, the sensor may comprise a plurality of sensors, positionedin one or more locations within the cavity.

In some embodiments, the BFM apparatus or system may include anaccelerometer for sensing an orientation or position of the patientwhich may affect one or more of bladder pressure and/or a bladderfullness measurement. Typically, the accelerometer will be operativelycoupled to the controller such that a signal(s) generated by theaccelerometer are received by the controller. The controller can includelogic for using the signals from the accelerometer to detect whether thepatient is in a particular position, for example, supine sitting,standing, or bent-over position. The controller may then makeadjustments for an amount of bladder fullness resulting in a notice oralert being sent to the patient, e.g., regarding bladder fullness, needto urinate etc. In particular embodiments, the controller includes logicto account for sudden changes in the patient’s orientation such thatduring that time signals from the BFM apparatus sensor are: i) gated outor otherwise not used by the controller in the determination of bladderfullness during the orientation change and fixed period afterward; ii)are adjusted to reduce their impact on bladder fullness determination bythe controller; and/or iii) are taken over a longer sampling period inmaking a bladder fullness by determination by the controller whenever anorientation change is detected. According to various embodiments, theaccelerometer may be directly affixed to the BFM apparatus, for example,to the base, or may be positioned external to the BFM apparatus andeither coupled by wire or wirelessly. For external positioningembodiments, the accelerometer may either be implanted or wornexternally by the patient.

In another aspect, the invention provides a method for monitoring thefullness of a bladder of a patient using one or more embodiments of thebladder fullness measurement (BFM) apparatus described herein. Themethod comprises positioning an embodiment of the BFM apparatus betweenthe patient’s pubic bone and the bladder such that the pressure sensoris subjected to force from the patient’s bladder (due to its degree offullness) but not substantially effected by force from tissue other thanthat from the bladder. In many embodiments, this can be accomplished bypositioning the back or base of the BFM apparatus so that it faces thepubic bone such that the base is mechanically supported by the pubicbone. Desirably, though not necessarily, the BFM apparatus is fixedlyattached to the wall of the patient’s bladder or to connective tissuesuch as fascia. This can be accomplished by suturing the base to thefascia via one or more suture holes in the base or other location on theapparatus. Also, through the use of conformable materials, the base ofthe apparatus can be conformed or otherwise shaped by the surgeon to thecurve of the patient’s pubic bone to use the patient’s pubic bone as oneapproach to shield the sensor apparatus from tissue forces other thanthat from the bladder. The base may be pre-bent before implantation tocontour matching that of the pubic bone or at the time of theimplantation.

In particular embodiments, the BFM apparatus may be positioned in apocket created by the surgeon in the fascia between the pubic bone andthe bladder wall. In one approach for doing this, the surgeon createsthe pocket and then slides the apparatus in the pocket and then suturesthe base of the apparatus to the connective tissue. This thickness ofthe apparatus and the base can be selected such that the surgeon needonly create a pocket of around 1 cm or less though, larger dimensionsare also contemplated.

Once positioned at a selected location in tissue between the patient’spubic bone and bladder, the BFM apparatus may be coupled to a controllerwhich receives signals from the BFM apparatus corresponding to an amountof fullness of the bladder. In particular embodiments, the controllermay be part of otherwise operably coupled to a closed loop urinationcontrol system. The BFM apparatus may be implanted in an on-state orswitched on once implanted. Once implanted and activated the BFMapparatus sends a signal (e.g., an output signal) corresponding to thedegree of distension or fullness of the bladder to the controller (thedegree of distention being synonymous with or otherwise correlated tothe degree of fullness of the bladder). The controller then uses thatsignal to perform one or more functions which may involve or relate tothe patient’s urinary function. In particular embodiments, the bladderfullness signal is used by the controller to initiate urination usingthe closed loop urinary control system.

In various embodiments, the BFM apparatus may be implanted in apre-calibrated state or may be calibrated after implantation as isdiscussed herein. It may also be implanted in an on-state or switched ononce implanted. Once implanted and activated, the BFM apparatus sends asignal to the controller corresponding to the degree ofdistension/fullness of the bladder. For embodiments that involve postimplant calibration, logic (e.g., programming) used by the controllermay be updated with the calibration value. The controller then uses thatsignal to perform one or more functions which typically will relate toor involve the patient’s urinary function. According to one or moreembodiments, the functions may include causing an associated implant(e.g., an implanted pulse generator or other neuro-stimulation device)to perform a function (e.g. stimulation of the pudendal nerve) orsending a notification or alert to the patient. The notification oralert may be sent to the patient for example via a cell phone or PDAdevice operably coupled to or otherwise in communication with thecontroller (e.g., via RF communication). The notification or alert maybe related to one or more of the following: the degree of fullness ofthe bladder, an estimated time when the bladder will be full, and a needto urinate based on the degree of bladder fullness. The alert on theneed to urinate may include a ranking of the need to urinate, such asimmediately (e.g., next five minutes), moderate (e.g., next five to tenminutes), or low (e.g., next 15 to 30 minutes).

In one or embodiments, the BFM apparatus or system may be calibratedafter implantation so as to calibrate the signal (electrical/analog ordigital) generated by the BFM apparatus to a degree of fullness of thebladder. In one implementation, this can be accomplished by filling thebladder with a known volume(s) of fluid using a bladder access devicesuch as a Foley or other urinary drainage catheter known in the art andthen measuring the signal (electrical or digital) produced by theapparatus in response to the degree of fullness. A calibration curve canbe developed and data can be then downloaded to the controller or otherlogic resources coupled to the BFM apparatus or system. Typically,several calibrations will be done over the first several months afterimplantation. The first may be done soon after implantation and thensubsequent calibrations may be done several months after implantation toaccount for a wound healing response in around the implanted BFMapparatus which may affect the deformability of the deformable membraneand/or the amount of force exerted by the bladder against the BFMapparatus in particular to the membrane.

In embodiments where the BFM apparatus includes an accelerometer thecontroller can include logic for using the signal from the accelerometerto detect whether the patient is in a particular position, for example,supine sitting, standing, or bent-over position. Based on the position,the controller may then make adjustments for an amount of bladderfullness resulting in a notice or alert being sent to the patient, e.g.,regarding bladder fullness, need to urinate, etc. In use, suchembodiments, provide for more accurate message being sent to the patientregarding the bladder and/or urination urgency status. In cases of thebent-over position, the controller may also send the patient an alert tosit up due to the increased pressure put on the bladder from being putin the bent-over position. The reasons being that such pressure mypossibly result in urinary linkage (incontinence) or urine being forcedback into the kidneys. In this way, embodiments of the inventionincluding an accelerometer, provide for the reduced possibility ofdamage to the kidney as well as urinary leakage for patients who havelost the ability to urinate due to spinal injury or other condition.

For a fuller understanding of the nature and advantages of the presentinvention, reference should be made to the following detaileddescription taken in conjunction with the accompanying drawings. Thedrawings represent embodiments of the present invention by way ofillustration. Accordingly, the drawings and descriptions of theseembodiments are illustrative in nature and not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of an embodiment of a bladder fullness measurement(BFM) apparatus.

FIG. 1A illustrates an embodiment of a bladder fullness apparatus havingmultiple sensors.

FIG. 2 illustrates a side view of an embodiment of the BFM apparatus ofFIG. 1 .

FIGS. 3A-3B illustrate placement of the bladder fullness measurementapparatus (BFMA) within the pelvic area of the patient. FIG. 3A is aperspective view showing placement of the BFMA within the pelvic area ofthe patient; FIG. 3B is a side view illustrating placement of the BFMAbetween the bladder and the pubic bone.

FIGS. 4A-4D illustrate placement of the BFMA in a surgical pocketbetween the pubic bone and the bladder wall. FIG. 4A shows creation ofthe pocket; FIG. 4B shows the advancement of the BFMA into pocket; FIG.4C shows positioning of the BFMA at a desired tissue site within thepocket; and FIG. 4D shows the BFMA sutured in place at the tissue siteand connection of the BFMA to an implanted controller.

DETAILED DESCRIPTION

Embodiments of the invention provide devices, systems, and methods formeasuring bladder fullness in a patient and providing information onsuch. Particularly, embodiments provide an apparatus and a system formeasuring and providing real-time information relating to the patient’sbladder fullness (from urine) based on bladder fullness due to urinevolume. The amount of bladder fullness is correlated to the amount ofbladder distention and accordingly, as used herein, the two terms areconsidered synonymous. Also, as used herein the term, “about” meanswithin ± 10% of a stated property, dimension, or other value and, morepreferably, ± 5% of the stated value. Also, as used herein, the term“substantially” means within ± 10% of a stated property or quality andwhere appropriate within a numerical value of a stated property orquality, more preferably, ± 5% of the stated property or quality.

Various embodiments of the invention provide sensors, apparatus andsystems for monitoring the bladder for degree and/or signs of fullness(i.e., due to contained urine) and providing information to the patienton the degree and/or signs of bladder fullness. Some embodiments providean apparatus for continuously monitoring the bladder for degree and/orsigns of fullness in order to initiate urination (aka micturition) forpatients who have lost voluntary bladder control and/or the ability tosense bladder fullness such as patients who have sustained a spinal cordinjury. Accordingly, various embodiments of the apparatus provided canbe configured to function as a bladder fullness measurement (BFM)apparatus to allow the patient and/or urinary control implant to utilizeinformation provided by the sensor on bladder fullness to initiate ortrigger micturition. Embodiments of the BFM apparatus provide theadvantage of eliminating the need for the patient to perform voiding attimed intervals by providing an output signal representative of currentbladder volume directly to the patient or an associated implant orsystem which the patient or system can then use to initiate micturitionand void the bladder.

According to one or more embodiments, signals generated by the BFMapparatus may be used to notify the patient of a degree of bladderfullness including, for example, full bladder status. The informationprovided by the signal can then be used by the patient to allow them toself-void or trigger an associated bladder control system having animplant to deliver electrical stimulation to the pudendal nerve or othertissue, to initiate voiding of the bladder when the bladder is full. Onesuch bladder control system is described in U.S. Pat. Application SerialNo. 15/410,692, entitled Systems And Methods For Patient-Enabled BladderControl which is incorporated by reference herein for all purposes.Embodiments of the BFM apparatus can also be used to monitor bladderfullness during voiding and provide a signal which is used to determinewhen to cease self-voiding or stimulation (e.g., of the pudendal nerve)to cause such when the bladder is voided to an acceptable residualvolume. In particular embodiments, the signal can be sent to a bladdercontrol system such as that described in U.S. Pat. Application SerialNo. 15/410,692 and used by the system to cease stimulation of pudendalnerve so as to cease voiding.

Referring now to the drawings, embodiments of an apparatus 110 andsystem 100 for measurement of bladder fullness will now be described.According to one embodiment depicted in FIGS. 1 and 2 , a bladderfullness measurement (BFM) system 100 includes a BFM apparatus 110 and acontroller 170 (described in more detail below). Apparatus 110 includesa base 120 comprising a flexible material, a rigid layer 130 attached tothe base, a deformable membrane 140 positioned over and hermeticallysealed to the rigid layer 130, and a pressure sensor 150. The base 120is configured to be positioned in and attached (e.g., via suturing) totissue T between the pubic bone PB and the bladder B. The base 120 maybe configured to be positioned near the patient’s pubic bone such thatmechanical support provided by the pubic bone to the base preventsmembrane 140 from being substantially deformed by force from tissueother than the bladder B. As used herein the term “substantially deform”means deformation in one or more dimensions of membrane 140 of more thanabout 10%, more preferentially, more than about 5%. In these and relatedembodiments, the base 120 may specifically be configured to conform to acontour C of the pubic bone so as to be mechanically supported by thepublic bone. According to one or more embodiments, the base may have acircular shape with a diameter 120D in a range from about 1.5 to 3.0 cmwith larger and smaller diameters contemplated. The shape and diameter120D of base 120 can be configured to place the base 120 at a desiredlocation at or near the patient’s pubic bone PB and bladder B includingbeing positioned against a section of the public bone facing thepatient’s bladder.

In various embodiments, base 120 may be configured to be sutured orotherwise affixed to tissue T. According to one embodiment, this may beaccomplished by the use of suture holes 121 placed at selected locationsin the base 120. In additional or alternative embodiments, this may beaccomplished by configuring base 120 to be sutured through by thepassage of a surgical needle or other like device through the base. Inthese and related embodiments, the material properties of the base 120are desirably configured to allow suturing through the base whileminimizing tearing of the base from suturing (e.g., by passing thesuture though the base) In particular embodiments, such tear resistancecan be achieved by fabricating the base 120 from a fibrous meshimpregnated with an elastomer. In or more embodiments, the fibrous meshmay correspond to DACRON (woven or knitted) and the elastomer tosilicone or polyurethane, with other fibrous materials (e.g., NYLON) andother elastomers known in the medical arts also considered. In specificembodiments for conferring tear resistance, the tear strength of thebase material in a range of about 0.5 to 20 lbs./inch with specificembodiments of 0.75, 1, 2.5, 5, 7.5, 10, 12, 15 and 17.5 lbs./inch.

The rigid layer 130 may comprise various metals (e.g., stainless steel)or rigid polymers known in the art e.g. polycarbonate or PMMA(Poly(methyl methacrylate)). In many embodiments, rigid layer 130 has anapproximate circular shape particularly those embodiments where the basehas a circular shape. Other shapes are also considered and the shape mayin some embodiments correspond to the shape of base 120. The rigid layer130 may have a diameter 130D in a range from about 0.5 to 1 cm withlarger and smaller diameter contemplated. Desirably, at least a portionof rigid layer 130 comprises a conductive material such as a metal orconductive polymer. That portion will now be referred to as a conductiveportion herein conductive portion, 130 c. Conductive portion 130 cserves to make electrical contact between the pressure sensor 150 and alead wire 160 or other electrical conduits so as to send signals fromthe sensor to an electrical device such as a controller 170 ortransmitter. In particular embodiments, the lead 160 can be coupled toconductive portion 130 c by means of a connector 165 in the form of atab 166 having one or connector electrodes 167 which may contact withindividual wires 168 of lead wire 160. Tab 166 or other connector 165can be covered by an insulative cover 169 which may comprise aninsulative polymer that is molded in place. The deformable membrane 140is sealed to the rigid layer 130 so as to define a cavity 135 betweenthe membrane and the rigid layer. The cavity 135 is filled with a fluid137 such a mineral oil or silicone. The membrane 140 is positioned andconfigured to deform from force exerted by the bladder B against themembrane so as to exert a pressure on the fluid 137, with the pressurebeing correlated to a degree of fullness of the bladder. A desired levelof deformability of the membrane 140 may be achieved by the selection ofits dimensions (e.g., thickness) and the use of various deformablematerials known in the material science arts such as metals and polymersincluding, various elastomers known in the art, e.g., silicone,polyurethanes and the like.

According to one or more embodiments, pressure sensor 150 is positionedon a portion of the rigid layer 130 within the cavity such that it isable to measure the pressure of the fluid within the cavity 135. Thesensor 150 is configured to generate a signal (electrical/analogue ordigital) correlated to the pressure within the cavity which is in turnis correlated to a degree of fullness of the bladder. Sensor 150 iselectrically coupled to the conductive portion 130 c of the rigid layersuch that signals generated by the pressure sensor can be transmittedvia conductive portion 130 c to a controller or other electricalcircuitry. The sensor 150 may be attached to the rigid layer 130 viavarious adhesives known in the art and may be electrically coupled tothe conductive portion 130 c by solder or other electrically conductivemeans. According to various embodiments, the pressure sensor 150 maycorrespond to one or more of a strain gauge, a solid state sensor or aMEMS-based sensor. In specific embodiments, the strain gauge maycorrespond to a Wheatstone bridge circuit known in the art. Also,according to some embodiments such as that shown in FIG. 1A, the sensor150 may comprise a plurality of sensors 150 p, positioned in one or morelocations within the cavity. Use of a plurality of sensors 150 pprovides the benefit of a more uniform measurement of pressure withincavity 135 to account for any differences in pressure within the cavity135 as well as providing redundancy should any individual sensor 150fail after implantation.

In many embodiments, system 100 includes a controller 170 for receivingsignals 111 (also referred as output signals 11), which may beelectrical or digital, from apparatus 110 and using information from thesignals 111 to perform one or more functions related to the monitoringand control of a patient’s urinary function. The controller 170 may becoupled (directly or operably) to the BFM apparatus via a lead wire orother electrical conduit 180 as is shown FIGS. 3 b and 4 a . Accordingto one or more embodiments, controller 170 comprises logic resources 171which may include or correspond to one or more of a microprocessor,application integrated circuit (ASIC) analogue device, state/machinedevice, or other logic resources known in the art. Controller 170 mayalso include or be operably coupled to memory resources 172 such as RAM,DRAM, SDRAM, SDR SDRAM, ROM, flash memory etc.; and a transmission meanssuch as an RF transmission device. Typically, the controller 170 willcontain logic in the form of electronic instruction sets which may be inthe form of a software module 173 that is operable on microprocessor orother logic resources 171. Module 173 may include algorithms forcontrolling one or more aspects of urination. Further description of theuse of controllers and algorithms for control of a patient’s urinaryfunction may be found in U.S. Pat. Application Serial No. 15/410,692,entitled “Systems And Methods For Patient-Enabled Bladder Control”,which is incorporated herein by reference for all purposes. Inalternative or additional embodiments, including those where controller170 corresponds to an analogue device, the logic used by controller 170(e.g., for utilizing signals from BFM apparatus 110 to perform one ormore functions) may be programmed in hardware.

In particular embodiments, controller 170 is configured to receive anoutput signal(s) 111 from the BFM apparatus 110 and use the signal todetermine whether a percentage change in the output signal 111 from theBFM apparatus 110 exceeds a predetermined threshold. The predeterminedthreshold is based on the percentage change between bladder volumesrepresenting “empty” and a particular degree of fullness. Upondetermining if the percentage change in an output signal received fromthe apparatus 110 exceeds the predetermined threshold, the controller170 may perform one or more functions. Those functions may include thesending of a notification or alarm to the patient when the fullness ofthe bladder reaches a desired level (e.g., full, near full, etc.). Thenotification or alarm may be sent to a dedicated device worn by thepatient that is in communication with the controller (wirelessly orotherwise) or to an external device such as a cell phone, tablet or likedevice. In addition, upon determining that the percentage change in theoutput received by the controller 170 exceeds the predeterminedthreshold, the controller may send a signal 175 cause an associatedimplant 200 to induce urination in the patient. Implant 200 maycorrespond to a pulse generator or other electrical neuro-stimulationdevice known in the art.

In some embodiments, the BFM apparatus 110 or system 100 may include anaccelerometer 190 for sensing an orientation or position of the patient(e.g., standing, lying down, etc.) which may affect one or more ofbladder pressure and/or a bladder fullness measurement. Typically,accelerometer 190 will be operatively coupled to controller 170 (oranother controller not shown but contemplated by embodiment ofinvention) such that signals 191 generated by the accelerometer(encoding information on the patient orientation or movement) arereceived by the controller. In an embodiment of system 100 or apparatus110 which includes an accelerometer, controller 170 can include logic(e.g., modules) for using signals from the accelerometer 190 to detectwhether the patient is in a particular position for example, supinesitting, standing or a bent-over position. Controller 170 may then makeadjustments for an amount of bladder fullness which result in a noticeor alert being sent to the patient, e.g., regarding bladder fullness,need to urinate etc. (e.g., the level of bladder fullness which triggersuch a notice or alert may be increased or decreased depending thepatient’s position, orientation, etc.). In particular embodiments, thecontroller 170 includes logic (e.g., in the form of modules 173) toaccount for sudden changes in the patient’s orientation such thatsignals 111 from the BFM apparatus sensor 150 during that time are: i)gated out or otherwise not used by controller 170 in the determinationof bladder fullness during the orientation change and a fixed periodafterward; ii) are adjusted to reduce their impact on bladder fullnessdetermination by the controller; and/or iii) are taken over a longersampling period in making a bladder fullness determination by thecontroller whenever an orientation change is detected. In use, suchembodiments provide for more accurate message being sent to the patientregarding the bladder and/or urination urgency status. In cases of thebent-over position, the controller may also send the patient an alert tosit up due to the increased pressure put on the bladder from being putin the bent-over position. The reasons being that such pressure maypossibly result in urinary linkage (incontinence) or urine being forcedback into the kidneys. In this way, embodiments of the inventionincluding an accelerometer, provide for the reduced possibility ofdamage to the kidney as well as urinary leakage for patients who havelost the ability to urinate due to spinal injury or other cause such asmultiple sclerosis.

According to various embodiments, accelerometer 190 may be directlyaffixed to the BFM apparatus 110 for example to base 120. Alternatively,it may be positioned external to the BFM apparatus and either coupled bywire or wirelessly. For external positioning embodiments, accelerometer190 will typically be configured to wirelessly communicate withcontroller 170 (or other controller) and may either be implanted or wornexternally by the patient. The wearable configurations for accelerometer190 may correspond to a band worn around the patient’s waist, arm orleg, or a skin adherent patch worn at one or more locations on thepatient’s body, e.g., arm, leg, torso, etc. In particular embodiments,multiple accelerometers 190 may positioned in multiple locations on thepatient’s body (e.g., lower leg, waist, neck, etc.) in order to make amore accurate determination of the patient’s exact position/orientation(e.g., standing, sitting supine, and the like).

A description will now be provided of embodiments of methods formonitoring the fullness of a patient’s bladder using one or moreembodiments of the bladder fullness measurement (BFM) apparatus 10described herein. One embodiment of such a method comprises positioningan embodiment of the BFM apparatus 110 between the patient’s pubic bonePB and the bladder B such that the pressure sensor 150 is subjected toforce from the patient’s bladder (due to its degree of fullness) but notsubstantially effected by force from other tissue (e.g., other than thebladder). In many embodiments, this can be accomplished by positioningthe back or base 120 of the BFM apparatus 110 so that it faces the pubicbone PB such that the base is mechanically supported by the pubic bone.Desirably, though not necessarily, the BFM apparatus 100 is fixedlyattached to connective tissue adjacent or near the bladder wall such asfascia F. It may also be directly attached to the bladder. Such fixedattachment can be accomplished by suturing the base 120 to the fascia orbladder wall via one or more suture holes 121 in the base or otherlocation on the apparatus. Also, according to some embodiments, the base120 of apparatus 110 can be conformed (e.g., bent) or otherwise shapedby the surgeon to the curve C of the patient’s pubic bone PB. These andrelated embodiments provide for the ability to use the patient’s pubicbone as one approach for shielding the sensor apparatus from tissueforces other than that from the bladder. Base 120 may be pre-bent beforeimplantation to a contour C matching or otherwise similar to that of thepubic bone or at the time of the implantation. Conformability of base120 can be achieved by the use of conformable materials, such as variousconformable polymers for all or a portion of base 120. In alternative oradditional embodiments, all or a portion of apparatus 110 including base120, can be configured to be foldable and unfoldable so that it can beinserted through tissue in a folded state so as to minimize the size ofincision made to access the patient’s bladder /pubic bone region andthen unfolded into an expanded state once it is positioned at a desiredimplantation site in the bladder /pubic bone region.

In particular embodiments, base 120 may be configured to be folded,furled, or otherwise sufficiently flexible to be inserted through astandard size laparoscopic trocar so to allow for placement of base 120at a desired implantation site using a laparoscopic surgical approachknown in the minimally invasive surgical arts. Various approaches andembodiments for obtaining a foldable base 120 may include the use ofshape memory super elastic alloys such as nickel titanium alloys anexample including, NITINOL. Shaped memory alloys are deformable metalalloys which are capable of being heated treated so as to remember ashape they are held in during heat treatment. This shape is known as thememory or original shape. When cooled below a first transitiontemperature (e.g., a martensitic transition temperature fornickel-titanium alloys) they become super-elastic and can be readilydeformed to assume a different shape (e.g., a deformed shape) from thememory shape. However when heated above the first transition temperatureto a second transition temperature (e.g., austenitic transitiontemperature for nickel-titanium alloys) they reassume their original ormemory shape. In this case, the memory shape for base 120 may correspondto the unfolded flat or slightly curved shape configured to bepositioned near or adjacent the pubic bone, while the deformed shapecorresponds to the folded or furled shape of the base for insertion andadvancement through a trocar or other minimally invasive surgicalintroducer known in the art. Also, the second transition temperature mayconfigured to be at or slightly below (e.g., within 5° C.) to that ofthe body temperature so that the once positioned within the body at aselected tissue site, the base will unfold to its memory shape fromheating provided by contact with body tissue and/or body fluids. In someembodiments, the surgeon may irrigate base 120 with hot water at orabove the transition temperature so as facilitate or accelerate thetransition of the base to its unfolded state. In use, these and relatedembodiments, provide the benefit of reducing the incision size forimplanting the apparatus 110 as well as allowing the surgeon to moreeasily manipulate and implant the apparatus in the body while the baseis in its unfolded state.

In particular embodiments, the BFM apparatus 110 may be positioned in apocket P created by the surgeon in the fascia F or other connectivetissue between the pubic bone BP and the bladder wall BW. Referring nowto FIGS. 4A-4D, in one approach for making such a tissue pocket, thesurgeon creates the pocket P and then slides the apparatus into thepocket and then sutures the base 120 to the connective tissue. Thisthickness of the apparatus 110 and/or that of base 120 can be selectedsuch that the surgeon need only create a pocket having a width of about1 cm or less though, larger dimensions are also contemplated.

Once positioned at a selected location in tissue between the patient’spubic bone PB and bladder B, the BFM apparatus 110 may be coupled to acontroller such as controller 170, which receives signals 111 from theapparatus corresponding to an amount of fullness of the bladder.Coupling may either be directly by a lead wire other electrical conduitor, wirelessly using an RF transmitter or other transmission means. Inparticular embodiments, the controller 170 may be part of or otherwiseoperably coupled to a urination control system 300 (aka urinary controlsystem 300) which may include or be configured as a closed loopurination control system. In various embodiments, the BFM apparatus 110may be implanted in an on or active state or switched to an active statefrom a sleep state (e.g., a low power state) or off state onceimplanted. Once implanted and activated, apparatus 110 sends signals 111corresponding to the degree of fullness of the bladder to the controller170. The controller may then use those signals 111 to perform one ormore functions which may be associated with the patient’s urinaryfunction including, for example, those involved with monitoring and/orcontrol of urinary function. In particular embodiments, signals 111 areused by the controller to initiate urination using a urinary controlsystem such as a closed loop urinary control system 300′ which may beassociated with and/or operatively coupled to an implantedneuro-stimulation apparatus 200 which may be part of urinary controlsystem 300. As such in these and related embodiments, urinary controlsystem 300 can be configured to initiate and/or control urination in thepatient based on signals 111 received from apparatus 110, which are usedby controller 170 to cause neuro-stimulation device 200 to stimulate thepatient’s pudendal nerve (or other appropriate portion of theirneuroanatomy) to initiate and/or control urination.

In various embodiments, the apparatus 110 may be implanted in apre-calibrated state or may be calibrated after implantation as isdiscussed herein. It may also be implanted in an active state orswitched to an active state once implanted as is discussed above. Onceimplanted and activated, the BFM apparatus 110 sends a signal tocontroller 170 corresponding to the degree of distention/fullness of thebladder to the controller (for embodiments that involve post implantcalibration, logic, e.g., programming) used by the controller may beupdated with the calibration value). The controller then uses thatsignal to perform one or more functions which typically will involve thepatient’s urinary function. According to one or more embodiments, thefunctions may include causing an associated implant 200 (e.g., animplanted pulse generator or other neuro-stimulation device) to performa function (e.g. stimulation of the pudendal nerve) associated withinitiating or performing a urinary function in the patient (e.g.contraction of the bladder) or sending a notification or alert to thepatient. The notification or alert may be sent to the patient forexample via a cell phone or PDA device operably coupled to or otherwisein communication with the controller (e.g., via RF communication). Thenotification or alert may related to one or more of the following: thedegree of fullness of the bladder, an estimated time when the bladderwill be full, and a need to urinate based on the degree of bladderfullness. The alert on the need to urinate may include a ranking of theneed to urinate, such as immediately (e.g., next five minutes), moderate(e.g., next five to ten minutes), or low (e.g., next 15 to 30 minutes).

In one or more embodiments, the BFM apparatus 110 or system 100 may becalibrated after implantation so as to calibrate the signals 111 (whichmay be electrical or digital) generated by the BFM apparatus 110 to aspecific amount of fullness of the bladder. In one implementation,calibration can be accomplished by filling the patient’s bladder with aknown volume(s) of fluid using a Foley or other urinary drainagecatheter known in the art and then measuring the signal 111 produced bythe BFM apparatus 110 in response. A calibration curve can be developedand data can be then downloaded to controller 170 or other logicresources coupled to the BFM apparatus 110 or system 100. Typically,several calibrations will be done over the first several months afterimplantation of the BFM apparatus 110 at a selected tissue site. Thefirst calibration may be done soon after implantation and thensubsequent calibrations may be done several months after implantation toaccount for a wound healing or related response in around the implantedapparatus 110. Such a wound healing response may alter the calibrationof the apparatus by changing or otherwise affecting the deformability ofthe deformable membrane 140 and/or the amount of force exerted by thebladder against the apparatus 110, in particular to the membrane 140 andpressure sensor 150. In use, the performance of subsequent calibrationsprovide for the ability of accounting for changes in the output of theapparatus (e.g., in output signals 111) caused by the wound healingresponse or other physiologic adaption of the patient’s body toapparatus 110, for example, protein, mineral, or cellular deposition,shifting position of apparatus within the patient’s body or shiftingpositions of the patient’s bladder and bone structure. This in turnprovides the benefit of more consistent and thus improved measurementsof bladder fullness by apparatus 110 over the implanted life of theapparatus. According to one or more embodiments, controller 170 mayinclude logic (e.g., in the form of software or other electronicinstruction set modules 173 herein modules 173) for determining: i) whenthe apparatus has come out of calibration; and then, ii) alert thepatient or physician of the need to do to a subsequent calibration. Thealert can be in the form of a message sent to an external communicationdevice such as cell phone in the patient’s possession or a message sentover the Internet or the cloud to the patient’s doctor or other medicalpractitioner. In one or more embodiments, the logic used by thecontroller for determining when the apparatus is out of calibration mayinclude an algorithm which analyzes changes in measured pressure over aselected length of time (e.g., days, weeks or months) and makes adetermination based on those change. In particular embodiments, thechange in measured pressure over time may correspond to a change inaverage measured pressure over time or a change in a moving average ofmeasured pressure over time. Preferably, though not necessarily, thechange in the average will be a statistically significant change (e.g.,a p-value less than 0.05, more preferably than 0.01) using one or morestatistical tests known in the art including, e.g., a T-test or an ANOVAtest.

Conclusion

The foregoing description of various embodiments of the invention hasbeen presented for purposes of illustration and description. It is notintended to limit the invention to the precise forms disclosed. Althoughembodiments are described in detail herein with reference to theaccompanying drawings, it is to be understood that the concepts are notlimited to those precise examples nor are the drawings necessarily drawnto scale. There may also be distinctions between the artistic renditionsshown in the drawings and the actual apparatus due to drawingperspective, the drawings not necessarily being to scale, sizeconstraints, manufacturing considerations and other factors. Also, thereare multiple embodiments which are not necessarily shown in the drawingswhich are nonetheless contemplated by the present disclosure.

Further, many modifications, variations and refinements of theembodiments described herein will be apparent to practitioners skilledin the art including for example those skilled in the medical implant,sensor, biosensor, neuro-stimulation and urinary device arts. Forexample, embodiments of the BFM apparatus and system can be sized andotherwise adapted for various pediatric and neonatal applications aswell as various veterinary applications. They may also be adapted forthe urinary tracts of both male and females. Further, those skilled inthe art will recognize, or be able to ascertain using no more thanroutine experimentation, numerous equivalents to the specific devicesand methods described herein. Such equivalents are considered to bewithin the scope of the present invention and are covered by theappended claims below.

Also, elements, characteristics, or acts from one embodiment can bereadily recombined or substituted with one or more characteristics oracts from other embodiments to form numerous additional embodimentswithin the scope of the invention. Moreover, elements that are shown ordescribed as being combined with other elements, can, in variousembodiments, exist as standalone elements. Further, for any positiverecitation of an element, characteristic, constituent, feature, stepetc., embodiments of the invention specifically contemplate theexclusion of that element, value, characteristic, constituent, featureor step. Hence, the scope of the present invention is not limited to thespecifics of the described examples, but is instead limited solely bythe appended claims.

What is claimed is:
 1. A method for monitoring the fullness of a bladderof a patient, the method comprising: fixedly positioning a bladderfullness monitoring apparatus (BFMA) between the patient’s pubic boneand their bladder such that the BFMA is subjected to force fromdistension of the patient’s bladder but is not substantially effected byforce from tissue other than that from the bladder; the BFMA configuredto generate an output signal corresponding to an amount of distension ofthe patient’s bladder; generating the output signal in response to theamount of distension of the patient’s bladder; and performing anelectronically controlled function when the output signal exceeds apredetermined threshold.
 2. The method of claim 1, wherein fixedlypositioned comprises suturing the BFMA to tissue adjacent the patient’sbladder or public bone.
 3. The method of claim 1, wherein theelectronically controlled function includes causing a notification to besent to the patient.
 4. The method of claim 3, wherein the notificationis an alert to the patient of a degree of bladder fullness or a need toinitiate urination.
 5. The method of claim 3, wherein the notificationis sent to an external communication device.
 6. The method of claim 5,wherein the communication device is a cell phone.
 7. The method of claim1, wherein the electronically controlled function comprisesneuro-stimulation of the patient’s neuroanatomy that controls or isinvolved in urination.
 8. The method of claim 7, wherein theneuroanatomy comprises a pudendal nerve.
 9. The method of claim 7,wherein the function comprises neuro-stimulation of the patient’sneuroanatomy to initiate urination.
 10. The method of claim 7, whereinthe neuro-stimulation is performed by an implant associated with theBFMA.
 11. The method of claim 10, wherein the implant comprises a pulsegenerator or other neuro-stimulation device.
 12. The method of claim 1,wherein the BFMA is attached to one of the bladder wall or tissueconnected to the bladder wall.
 13. The method of claim 1, wherein theBFMA is mechanically supported by the patient’s public bone.
 14. Themethod of claim 13, wherein the BFMA includes a tissue conformableportion and said portion conforms to a contour of the pubic bone. 15.The method of claim 1, wherein the electronic control of the function isperformed by a controller operatively coupled to the BFMA.
 16. Themethod of claim 15, wherein the controller is operatively coupled to orintegral with an associated implant that performs the electronicallycontrolled function.
 17. The method of claim 16, wherein implantcomprises a pulse generator or other neuro-stimulation device.
 18. Themethod of claim 1, further comprising: calibrating the output signal toan amount of bladder distension or fullness.
 19. The method of claim 18,wherein the calibration comprises filling the bladder with a knownamount of fluid using a bladder access device and measuring the outputsignal.
 20. The method of claim 19, wherein the bladder access device isa urinary drainage catheter or a Foley catheter.
 21. The method of claim1, further comprising: sensing an orientation of the patient, theorientation including at least one of standing, sitting, sittingbent-over or lying down.
 22. The method of claim 21, wherein theorientation is sensed using an accelerometer.
 23. The method of claim21, further comprising performing another electronically controlledfunction based on the sensed orientation of the patient.
 24. The methodof claim 23, wherein the other electronically controlled function isperformed by a controller.
 25. The method of claim 24, wherein thecontroller adjusts the threshold based on the sensed orientation of thepatient.
 26. The method of claim 24, wherein the controller gates outthe output signal based on the sensed orientation patient.
 27. Themethod of claim 21, wherein the sensed orientation is sitting in asitting bent-over position and the controller sends the patient analert.
 28. The method of claim 27, wherein the alert comprises a messageof a need to initiate urination.
 29. The method of claim 27, wherein thealert comprises a message to sit up.